The present invention is directed to a novel apparatus and method for making improved corrugated packages.
Corrugated packaging has been known for many years. However, there is a substantial need for a machine and a process which will produce improved corrugated packages of a selected size on a high volume basis from inexpensive starting materials. For example, in the food merchandising industry there is a need for a disposable paper package for use in making and shipping products such as layer cakes. Such a process and a machine should be capable of making the desired package from relatively inexpensive starting material, such as paper, to minimize the cost of the package to the consumer. The process and machine further should be capable of producing a completed package automatically, on a high volume basis and with minimum labor costs, to meet the need in industry for packages, and to diminish the per unit cost.
In accordance with this invention, the machine and process accommodates high-speed production of corrugated packages from inexpensive stock sheet material by functioning to automatically sequence the sheet material through steps which form a multiple-ply corrugated package side wall from the sheet material simultaneously with the formation of the package, so that completed packages can be discharged from the machine on a high volume basis. Speed is enhanced and costs are reduced by this machine and process by starting with flat stock sheet material which can be economically purchased in bulk. This flat material then is corrugated and formed into a package by the machine and process of this invention. The result is the high-speed production of uniform corrugated packages with efficiency and economy. Moreover, volume production can be increased further because the machine and process of this invention can be joined and operated in tandem or multiple-unit arrangements, so that a plurality of units work in unison to multiply the production capabilities of the machine and process.
Generally, the machine in accordance with this invention includes a rotatable corrugation head having a front face and a fluted periphery. This head is arranged to be rotated through several cycles of operation, with each cycle preferably encompassing one hundred and eighty degrees of rotation. The head incorporates means to secure material to its face and perpiphery during the operation of the machine. Preferably, the securing means includes vacuum ports in the periphery and the front face of the head which selectively apply a partial vacuum pressure or suction force to sheet material positioned adjacent the front face or the periphery, to thereby secure the material to the rotating head.
The machine also includes corrugating means, such as a movable corrugating roller, arranged to move into association with the head and mesh with the flutes on the head periphery. The roller and the head function to corrugate a sheet of material which is directed therebetween as the head is rotated. Actuation means, such as a pneumatic or hydraulic cylinder, are arranged for selectively moving this corrugating roller between a disengaged position and an engaged position mating with the fluted periphery of the head.
The machine also includes means for feeding an inner sheet of material of a selected length and width from a bulk material source into a position between the corrugating roller and the head. During operation of the machine, this sheet forms the inner corrugated ply of the side wall of the package. Suitable cutting means cut the inner sheet of material to a selected length after the leading edge of the material has been secured between the corrugating roller and the corrugation head. A sheet measuring and slack tape-on device is provided between the material source and the material feed to pre-measure the selected length of material to be fed, and to increase the accuracy of the feeding by isolating the material feed from the load of the bulk material source and by applying a linear tension force to the sheet.
A mechanism also is provided for placing a bottom wall member in association with the corrugation head, so that the function of the machine secures the bottom wall to the side wall as the side wall is being formed. In this respect, the machine includes means for transporting a bottom wall member having a selected shape and an outer edge from a supply source into engagement with the front face of the head, with the edge of the bottom wall aligned with the fluted periphery of the head. Means, such as the above-described vacuum ports, secure this bottom wall member for rotation with the corrugation head. Actuating means such as a pneumatic or hydraulic cylinder move the transport means between a disengaged position removed from the head, into an operating position which places the bottom wall member against the face of the head.
The machine in accordance with this invention also generally includes sealing means movable into association with the corrugation head for joining an outer sheet of material to the corrugated inner sheet. The outer sheet of material has a width greater than the width of the inner sheet, and a selected length, so that the outer sheet can be placed over the inner sheet to extend over the edge of the bottom wall member described above. Actuating means, such as pneumatic or hydraulic cylinders, selectively move this sealing means between a disengaged position and an operating position in association with the head.
The machine also has means for feeding a selected length of the outer sheet from a bulk supply source to a position between the sealing means and the head, for forming the outer sheet of the package and joining the corrugated side wall to the bottom wall upon rotation of the head. In the preferred arrangement, the actuating means for the sealer is arranged to clamp the leading edge of the outer sheet to the corrugating head, and the feeding means includes cutting means, to cut the outer sheet to a selected length after the material is so clamped. As described above with respect to the inner sheet, the feeding means for the outer sheet also includes measuring and slack take-up means arranged to provide a pre-measured material for said feeding means, and to isolate the feeding means from the load of the inner sheet bulk supply source.
In the preferred embodiment the engageable portions of the inner and outer sheet, and the bottom wall member, are provided with a heat seal coating, and the sealing means is a heat source which heats and seals the outer sheet to the inner sheet, and simultaneously seals the outer sheet to the bottom wall member, to form the corrugated side wall and the package simultaneously. The sealing means also preferably includes means for folding and sealing the extending edge portion of the outer sheet against the bottom wall member to form a frangible joint along which the side wall comprising both the inner and outer sheets, can be readily removed from the bottom wall. The adjacent ends of the corrugated inner sheet are abutting but preferably not overlapping; to facilitate the removal of the side wall from the bottom wall. In the preferred embodiment, the sealing means also operates so that the outer sheet is sealed only to the bottom wall for a portion of rotation of the head, to form a relatively free pull tab portion on the side wall.
The machine in accordance with this invention also includes a mechanism for removing a completed package from the corrugation head. In the preferred form, this mechanism includes clamping means to grip the side wall of the package, preferably assisted by a vacuum force drawn through ports provided in the clamping means. The clamping means is driven, by pneumatic or hydraulic cylinders or other suitable means, to remove the package axially from the head, and then operates to discharge the package into a selected location, such as onto a conveyor belt for moving the packages to a subsequent operating station. This discharge of the package from the clamping means can be assisted by the reversal of the vacuum force in the ports of the clamping means, to apply a positive pressure force to the package. Additionally, the ports in the clamping means can be arranged at an angle to further assist the discharge of the package in the proper direction away from the corrugation head.
The method of forming a corrugated package in accordance with the present invention generally includes the steps of corrugating an inner sheet of material having a selected width on a rotatable corrugation head while forming the material into a shape defining a portion of the package side wall, and moving a bottom wall member adjacent the corrugated inner sheet so that an outer edge of the wall member is aligned with the corrugation portion of the inner sheet. An outer sheet of material having a width greater than the width of the first sheet is then wrapped around the corrugated inner sheet so that a portion of the outer sheet projects over the outer edge of the bottom wall. The outer sheet is then simultaneously joined with the corrugated portion of the inner sheet and the bottom wall member so that the outer sheet forms an outer ply of the side wall and joins the side wall of the package to the bottom wall. The method thereby forms a corrugated side wall and forms the package substantially simultaneously. In the preferred arrangement, several additional steps are included to perform the above-noted method in a preferred manner, to provide the package with a pull tab and to otherwise facilitate removal of the side wall from the bottom wall. The method concludes with discharging the completed package from the corrugation head.